Headlight



0. WINSTON.

HEADLIGHT.

APPLICATION men MAR. s. 1911.

Patented Oct. 19, 1920.

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HEADLIGHT. APPLICATION man MAR.8.!9I7.

Patented Oat. 19,1920.

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HEADLIGHT.

APPLICATION man MAR. s. 1917.

1,355,877. Patenwd 0013.19, 1920.

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HEADLIGHT. I APPLICATION FILEIDI MAR. 8.19M. 1,355,377, I Patented Oct. 19,1920.

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- @uer/on m gw/lw 5) ///5 A Woe/V575 UNITED STATES OVERTON WINSTON, OF MINNEAPOLIS, MINNESOTA.

HEADLIGHT.

. Specification of Letters Patent.

Application filed March 8, 1917. Serial No. 153,342.

T 0 all 10 from it may concern:

Be it known that I, Ovnnron WINsToN, a citizen of the United States, residing at M1n neapolis, in the county of Hennepln and State of Minnesota, have invented certain new and useful Improvements in Headlights; and I do hereby declare the following to be a full, clear, and exact descrlptlon of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to headl ghts and is particularly directed to the provlslon of an improved form of lens and to an 1mproved relative arrangement. thereof, 1n respect to a concave reflector and electric llght source within the latter.

In the accompanying drawings which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings;

Figure 1 is a vertical section showing a headlight embodying my invention and wherein a two-filament light bulb is employed as a means for shifting the llght source from the axis of the reflector to a point vertically above said axis;

Fig. 2 is an elevation looking at the inner face of the lens;

Fig. 3 is a fragmentary view in 1nner face elevation showing, on an enlarged scale, one of the prismatic sections of the lens Fig. 4 is a section on the line 44 of F1gs. 2 and 3; i

Figs. 5 to 14, inclusive, are sections taken on the corresponding section lines marked on Fig. 3;

Fig. 9 is an enlargement of the prismatlc section shown in Fig. 9 indicating the travel of a ray of light in passing thereto, therethrough, and therefrom;

Fig. 15 is a view corresponding to'F g. 1, but showing a headlight. having a single filament light bulb and a slightly mod1 fied lens;

Fig. 1.6 is an elevation looking at the inner face of the lens in Fig. 15;

Fig. 17 is a fragmentary view 1n 1nner face elevation, on an enlarged scale, of one of the prismatic sections of the lens shown in Fig. 16;

Fig. 18 is a section on the hue 1818 of Figs. 16 and 17;

Figs. 19 to 29,inclusive are transverse sections taken on the corresponding section lines of Fig. 17

Fig. 30 is an enlargement of the prism shown in Fig. 24.

Of the parts of the headlight the numeral 31 indicates the casing, the numeral 32, the clamping ring thereof, the numeral 33 the concave reflector, the numeral 34 the electric light bulb and the numeral 35 the lens. The reflector 33 is preferably a hyperbolic reflector and it is providedwith an axial passage through which the shank of the light bulb 34 projects and is held by a suitable support. This bulb support, so far as this invention is concerned, may be of any suitable construction, but as shown, comprises a shank engaging sleeve 36 and atubiilar socket 3'7 screwed into a flanged hub 38 secured to the back of the reflector.

The bulb shown in Fig. 1, is a two-filament bulb, the one filament having its hot spot at a and the other having its hot spot at'b. The point a is at the'axis of the refiector and preferably, also, at the focal center thereof. The point I) is vertically above the axis of the reflector. By means of a three-lead circuit 39, 40 and 41, which includes a battery 42, and switches 43 and 44,

Patented Oct. 19, 1920.

either of the two filaments a and b may, at

will, be energized and used as the light source of the headlight.

In the headlight illustrated in Fig. 15,

the light bulb 34 is provided with a single filament c, the hot spot of which is at the axis of the reflector and preferably also at the focal center thereof. This filament is connected to a battery or source of electrical energy 45, by leads 46 in one of which is'a switch 47 We will now consider the novel construction of the lens, the preferred form of which is illustrated in the drawings and which, described in detail, is asfollows:

One face of the lens, preferably its inner face, is formed with prismatic surfaces that extend horizontally across that face of the lens. The beveled surface of all of the prisms diverge downwardly from the plane of the lens, but the different prisms have a different bevel.

The prisms having the greatest maximum bevel are approximately at a horizontal line that intersects the axis of the lens and headlight, and in the lens illustrated, these horizontal prisms have a maximum downward divergence or bevel of nineteen degrees to the plane of the lens.. The bevel of thesuccessive prisms, in directions both vertically upward and vertically downward from the said horizontal line, progressively decrease, preferably in a constant order of succession For example, with the varia tion in the. maximum bevel of the successive prisms may be as indicated by the small numerals adjacent to the right hand edges thereof, in Fig. 2, by reference to which it will be noted that the uppermost prisms have a maximum bevel of only one degree to the plane of the lens and the bevel of the prisms above the horizontal central line increase in a downward direction one degree, each over the other, while the prisms that are below the said horizontal line progressively decrease in a downward direction.

Each prism has a maximum bevel at its outer ends and progressively decreasing bevel toward a vertical line that intersects the axis of the lens. In the lens illustrated in Figs. 1 to 14, inclusive, the different prisms have a maximum bevel at their ends indicated by the small numerals marked adjacent thereto on Fig. 2, and this maximum bevel decreases in both directions from the ends toward said central vertical line and diminishes approximately to zero at the said vertical line.

In the lens shown in Figs. 15 to 30, inclusive, the prisms, at the right and left hand extremities, have the same maximum bevel, as above stated, and as indicated by the small numerals marked at the right thereof in Fig. 16, but instead of decreasing to zero at a vertical line intersecting the axis of the lens, they decrease to angles that are approximately one-half the said maximum angles. For example, the prism having a maximum bevel or eighteen degrees at its extremities would decrease to an angle of nine degrees at the central vertical line and the upper and lower prisms which have a maximum bevel of one degree at their extremities, would decrease to an angle of one half degree to the said vertical line.

\Vith the above described arrangement, the prisms that are nearest to a horizontal line intersecting the axis of the lens, give the greatest downward deflection to the light rays, but in any particular prism, the greatest deflection of the light produced thereby will be from the outer extremities thereof and there will be progressively decreasing downward deflection toward a vertical line that intersects the axis of the lens. This gives a general downward deflection of the light beams but gives a less downward deflection to the more intense rays from the back of the reflector with the result that there is produced a long beam projection of the intense light rays suitable for country road driving and a downward diffusion of the less intense rays for the purpose of lighting the road.

In Fig. 1, the lighter'ray lines indicate the light rays when the light source is at a and the heavier ray lines, the rays when the light source is at the vertically offset point I). It will thus be observed that the light beam is given a greater downward deflection when the light source is at (0 than when the light source is at b.

Obviously, the best light beam for country road driving is produced when the light source is at a and the best light beam for city street driving is produced when the light source is at b. It is not desirable to give this great downward deflection to the less intense rays from the upper portion of the reflector as is given to the more intense rays from the back of the reflector.- It is desirable to get a maximum amount of intense rays on the road, but it is also desirable to diffuse some of the less intense light rays so as to light up objects above the road and at the sides of the road, and for this reason, the prisms nearest to the horizontal plane of the axis of the reflector are given greatest bevel and those nearest the top and preferably also those nearest the bottom are given decreased or less angle.

In the use of a headlight with an ordinary reflector adjusted so as to throw approximately the lower half of the light beam upon the ground, which is quite a common arrangement, the lower half of the light beam will be distributed over many hundreds of square feet of road surface, and per unit of surface, the road will be given but a very small percentage of light, as compared with the amount of light thrown upon a vertical object in the road, by the upper half of the light beam. This is a result just reverse from that desired. An ideal arrangement would be one in which there would be at least as much light, per unit of surface, thrown upon the road, as there would be upon a vertical object above the road; and such an arrangement, obviously, requires very much the greater part of the light beam to be distributed on the ground and a very minor part of the light beam to be diflused above the road. This ideal result is closely approximated by the use of the improved lens above described, which, as already stated, produces very great downward deflection of the more intense rays of the light beam and difl'uses some, or a minor part of the less intense light rays above the road.

What I claim is:

1. A lens for headlights having parallel prisms beveled in the same general direction, said prisms having minimum bevel at intermediate points and having bevels, the

angles of which progressively increase in both directions from said points of minimum bevel toward their ends.

, 2. A lens for headlights provided with parallel prisms, said prisms, among themselves, having bevels that, in respect to the basal surface of the lens, vary along a diameter perpendicular to the edges of said prisms, the individual prisms, in themselves, havin bevels, the angles of which, in a directlon from the rim of the lens inward decrease progressively in respect to the basal surface of the lens.

3. A lens for headlights having horizontal prisms beveled in the same general direction, said prisms, among themselves, having in respect to the basal surface of the lens, angles that, in a downward direction progressively increase their bevel to said basal surface, said prisms, in themselves, having bevels, the angles of which progressively increase in opposite directions from intermediate points of minimum bevel.

L. A lens for headlights provided with a group of prisms with major refracting surfaces beveled in'the same general direction, and which prisms, among themselves, increase the angles of their bevel in respect to the basal surface of the lens in the direction of a perpendicular to the edges of said prisms, said prisms, in themselves, from said perpendicular toward the rim of the lens having increasing bevels.

5. A lens for headlights provided with a group of prisms with major refracting surfaces beveled in the same general direction, and which prisms, among themselves,

progressively vary the angles of their bevel in respect to the basal surface of the lens in the direction of a perpendicular to the edges of said prisms, said prisms, in themselves, from said perpendicular toward the rim of the lens having increasin bevels.

6. A lens for headlights provided with a group of prisms with major refracting suraces beveled in the same general direction, and which surfaces, among themselves, increase the angles of their bevel in respect to the basal surface of the lens in a downward direction perpendicular to the edges of said prisms, said prisms, in themselves, from said perpendicular toward the rim of the lens having increasing bevels.

In testimony whereof I afiix my signature in presence of two witnesses.

OVERTON WINSTON.

Witnesses:

BERNICE G. WHEELER, HARRY D. KILGORE. 

